Cardiopulmonary Thromboembolism Detected by Tc-99m MH-1 Antifibrin Antibody

A patient with shortness of breath had a high probability lung scan for pulmonary embolism, but no obvious embolic source. Whole-body scintigraphy using Tc-99m labeled Fab' antifibrin monoclonal antibody showed large central pulmonary emboli as well as tracer uptake in the right atrium and aortic arch. No lower extremity clot was detected. This case shows significant differences in the appearance of pulmonary embolism as assessed by direct clot and ventilation-perfusion scintigraphy. It shows the importance of the heart as the origin of pulmonary emboli and the utility of direct thrombus visualization.